Ndjamena, Chad (CNN) -- The Arabic nomads in central Chad always have moved from place to place, following the rains with their camels and cattle. But in that parched stretch of Africa, some nomads have stopped moving, saying the droughts now come too often.
Chad is one of eight countries on the Sahel, a belt of arid land that stretches across Africa below the Sahara Desert. The region has always been prone to drought, but residents and aid workers say this year is the worst they've known.
The situation has prompted the United Nations Children's Fund (UNICEF) to launch a global social media campaign to raise awareness about the region's children, who are now in urgent need of food aid.
One of those children is an 18-month-old boy named Goni, who lies in a nutritional center, his hands bandaged so he doesn't pull out the feeding tube that keeps him alive. His mother, Saidi Mohamed, sits next to him in despair.
"This year, I didn't harvest anything. Even the seeds didn't grow. We couldn't even eat the seeds because everything was lost," says Mohamed.
Like others at the center, Mohamed used to depend on money sent by relatives working in Libya -- but when the revolution took place there last year, her family fled and the help disappeared. Now, she can't afford food at the market because the prices have risen so high.
"I have some hope because my child is feeling better," Mohamed said. "When he arrived, he couldn't even open his eyes. (But) when he recovers fully, I will have no other option but to go back to our village."
Across the Sahel, the crops have failed and hunger and malnutrition loom large. UNICEF says more than 10 million people are in danger of starving to death, and that 1 million children are at risk of malnutrition.
Halima Adoum says she had to watch her son die because he didn't have enough to eat. After locusts and droughts destroyed her crops, she wasn't able to pay for food.
Adoum resorted to feeding grass to her 4-year-old son Ahmed, who then died.
"When my son died, I was in shock. I was just in shock," Adoum said.
She said she has nothing for her remaining four children. Her one thought is of getting by.
"Every day, I am just thinking, 'How am I going to get food?' Again and again, 'How am I going to get food? How am I going to get food?'"
The crisis was set in motion last year with a lack of rains and drought, and it has grown worse because the drought has continued, UNICEF officials say.
With less food being grown, people are starting to sell their personal belongings and livestock so they get by in the coming weeks -- but that doesn't take care of their needs long-term, said UNICEF Executive Director Tony Lake, who spoke to CNN on a dry plain in Banda, south of Chad's capital, Ndjamena.
Rising food prices are another problem. And Mali, another country in the Sahel, is coping with thousands of refugees after a military coup there last month.
Lake said it's clear the region is on the threshold of a crisis and that now is the last chance to act.
"If you have an earthquake, or if you have a flood, you don't have much in the way of advance warning -- a little with a flood, none with an earthquake -- so you have to respond as quickly as you can," he said. "Here we know it's coming. Here, there's absolutely no excuse."
UNICEF's campaign, called #SahelNOW, asks users on Facebook, Twitter and other social media to post messages to spread word of the problem and raise funds for affected children.
The fund hopes to raise $120 million to treat and feed the region's children. At this point, UNICEF says it has about $30 million on hand.
In Chad alone, more than 6 million people have been affected by the crisis, with 3.5 million of them younger than 18. An estimated 127,300 children under age 5 are already suffering from severe acute malnutrition, UNICEF says.
The country also has the highest numbers of polio cases in Africa and is dealing with a meningitis outbreak, diseases that could complicate children's needs amid the crisis, the organization says.